The invention relates to a ruminant animal feed supplement and more specifically to a supplement and feed process which permits ruminant animals to be fed increased amounts of fatty acids in their diet while protecting the micro-organisms within the ruminants' stomachs from attack by the fatty acids.
Ruminants, particularly dairy cattle, have high energy demands during the lactation period, especially during the first one-third of the lactation period. During these periods of higher milk production, conventional cattle feeds, such as corn and alfalfa, lack the energy dairy cattle require. As a result, dairy cattle often do not maximize milk yields during this period and also tend to lose body weight due to energy deficiencies in the diet. Fat is an excellent source of energy, if digestibility problems which result from fat intake can be overcome. It has been suggested that, if the proportion of fat or fatty acids in cattle feed, especially during the lactation period, could be increased, the cattle could produce higher milk yields with increased butter fat content without losing body fat and without diminishing the proportion of milk fat in the milk produced.
Recent articles including Pertelsen, A., Feedstuffs (Jun. 27, 1983); Jimenez, A. A., Feedstuffs (Aug. 18, 1986); and Palmquist, D. L., Animal Health and Nutrition (Feb. 19, 1987) all recognize that the addition to fat or fatty acids to conventional dairy rations results in benefits which tend to relieve this energy shortage. However, conventional fats, such as tallow or animal fat, soybean oil, cottonseed oil, etc. tend to have a deleterious effect on rumen microorganism populations if added at rates of more than 2-3%. The reason is that, as the supplement enters the rumen, fatty acids attack the microbes which normally digest fiber, protein, and carbohydrates in the food. Without these microorganisms, decreases in milk production are likely to result.
As a result, the use of increased fats or fatty acids to the diet is not as simple as first appears. It is thought that conventional fats interfere with the digestability of feed components by (a) coating the fibrous portion of the diet with lipids which prevent attack by microbes; (b) modifying the rumen population concerned with cellulose digestion; (c) inhibiting the activity of rumen microorganisms; or (d) reducing the retention of calcium due to excessive excretion of soap in the feces. It is also been proven (Palmquist, D. L. and T. C. Jenkins, Journal of Dairy Science, 63:1 (1980) and Chalupa, W. et al., Journal of Dairy Science, 67:1439 (1984) and Chalupa, W. et al., Journal of Dairy Science, 69:1293 (1986)) that "unsaturated" fats have more harmful effects than "saturated" fats. As used herein, the terms "unsaturated", "saturated", and "highly saturated" should be defined. "Unsaturated" fats are those, such as soybean oil, which have an iodine value of 125 or more. "Saturated" fats, such as tallow, are those having an iodine value in the range of 50. Even at this relatively low iodine value, tallow still contains more than one-half unsaturated fatty acids. In further discussion hereinafter, the term "highly saturated" will be used to denote a product that has been chemically altered by being saturated or hydrogenated to form a fat or fatty acid with an iodine value of 35 or less. The iodine value is a measure of the liquidity of the fatty acid, the higher the value, the more liquid the material.
It has previously been proposed to protect the microorganisms in the rumen from attack by fatty acids in various ways. First, fats have been coated with proteins which were then treated with formaldehyde. These cross-linked proteins were "protected" from microbial digestion and the encapsulated fat escaped through the rumen to the abomasum and lower digestive tract. Recently, formaldehyde has been found to have adverse or undesirable physiological effects which preclude the use of formaldehyde and, therefore, the use of this method of providing protein coated fats in dairy feeds.
Another approach involves the use of saturated (iodine value of 35-45) fatty acids in powdered form. Because of their relatively high melting point, the saturated fatty acids move through the rumen without much effect on rumen microorganisms. (See Canadian Patent No. 1,187,732 to Schaub.) The products presently which include saturated fatty acids, however, have prices which cause them be economically marginal or unacceptable.
In the Palmquist et al. U.S. Pat. No. 4,642,317, issued Feb. 10, 1987, there is disclosed a process whereby calcium salts of fatty acids are used to supplement dairy rations. Fatty acids in the form of calcium salts are inert in the rumen and have no apparent negative effects on fermentation. The high pH of the rumen allows these soaps (calcium salts) to move through the rumen without effecting digestion after which they are subsequently split and digested. The Palmquist et al. technique has attained some popularity, however, its cost causes this technique to be economically marginal.
In another approach, saturated fatty acids are formed by hydrogenation process and the glycerides or triglycerides are removed. It is thought that these fatty acids, because they are in free fatty acid form, may still be toxic to rumen microorganisms, although to a lesser extent than unsaturated fatty acids or conventional fats. The resulting product has achieved only limited success and further improvement is believed necessary before such approach becomes acceptable.
There is, therefore, a need for a feed supplement by which ruminants, particularly dairy cattle, can be fed fatty acids at economically productive rates while protecting the rumen microorganisms from the deleterious effects of the fatty acids.